It is well known that analog computation may be done with mechanical moving parts, such as gears, cams, cables, chains, pulleys, rotating shafts, racks and pinions, mechanical linkages, disks, slides and slots. With these mechanical components, computations such as addition, subtraction, multiplication, integration, coordinate conversion from polar to rectangular, and calculations of functions of multiple variables may be achieved. For example, analog mechanical computers that were used for naval gun fire control in World War II were capable of highly complex computations.
It is also well known that digital logic gates may be constructed from mechanical moving components. For example, AND, OR and NOT gates may be so constructed, allowing Boolean functions of arbitrary complexity to be calculated with mechanical moving parts. Furthermore, both analog and digital computers may be made from mechanical moving components.
A major problem with mechanical computers, however, is that their manufacture has required assembly of the parts of which they are comprised. That is, it has been necessary, after the mechanical parts are made, to put them together to make the computer. If done by hand, this assembly is time-consuming, expensive and requires highly trained technicians. Assembly may be automated, at least to some extent, but such automation becomes increasingly difficult and expensive as the complexity of the mechanical computer increases. Moreover, automated assembly tends to be inflexible and unable to handle changes in design of the computer.
Conventionally, the separate step of assembly is considered indispensable in any manufacturing process, including the manufacture of computers. For example, according to the home page for Assembly Magazine (http://www.assemblymag.com/HTML/69086047124f9010VgnVCM100000f932a8c0), May 7, 2010:                “Product assembly is arguably the one indispensable function that must occur in every manufacturing industry. Without the ability to assemble their products, manufacturing companies could not manufacture, and would not exist as we know them.”        